Hirsutism is excessive hair growth in certain areas of a woman's face and body, such as the mustache and beard area, that creates a "male pattern" of hair. Women normally can have fine, pale, faintly visible hair in these areas, but heavy hair growth in a male pattern with coarse or colored hair is not expected.
Normal patterns of hair growth and hair distribution vary widely, determined mostly by racial background. For example, whites as a group have more facial and non-scalp hair growth than do blacks or Asians, and white women of Mediterranean heritage normally have more hair growth than do women from Nordic countries.
Hirsutism in women means that hair follicles are being over-stimulated by testosterone or other androgen hormones. Androgens are the dominant sex hormones in men. Women normally have low levels of androgens. Hirsutism can be caused by abnormally high levels of androgens or abnormal stimulation of hair follicles even when androgen levels are normal.
In some cases, the extra androgen comes from medications such as certain progestins used in some brands of birth control pills or bodybuilding steroids that contain androgens or have some effects similar to androgens. Other medicines may indirectly cause the body to manufacture extra androgen hormones. These include some medicines to treat nausea, schizophrenia, agitation, epileptic seizures, migraine headaches, bipolar disorder, aggression and high blood pressure, as well as estrogens and opiate medications.
Occasionally, the overproduction of androgen hormones is caused by an abnormality in the ovaries, the adrenal glands or the pituitary gland of the brain.
Some excessive hair growth does not fit the pattern of growth triggered by androgen hormones (for example, hair between the eyes, on the forehead, on the temples or high on the cheeks of the face). This hair growth, called hypertrichosis, can be caused by thyroid problems or by anorexia nervosa. It also can result from long-term use of certain oral medications, including cyclosporin (Neoral, Sandimmune, SangCya), phenytoin (Dilantin), minoxidil (Loniten), and penicillamine (Cuprimine, Depen).